The technique of aqua dissection, which uses a high-pressure sterile liquid jet fed to a simple hand unit or to one with aspiration like that described in the published patent application WO 9703713 by SAPHIR MEDICAL, is known.
The action of the high-pressure liquid is a tissue cutting action which is more or less incisive depending on the pressure value.
There are other hand units which are used for rinsing or for lavage, with the sterile liquid distributed in that case under low pressure with adjustable flow.
The sterile liquid is delivered by a source adjustable either in pressure or in flow, for example, that of the generator described in publication WO 9428807 by SAPHIR MEDICAL.
This generator comprises a leak-proof chamber enclosing a flexible pouch containing the sterile liquid. The inner volume of the chamber is adjustably pressurized with a neutral gas. The pneumatic force of this gas expels the sterile liquid from the pouch to the output line. Depending on the hand unit type, i.e., dissection or lavage/rinsing, the liquid coming out is used under pressure or in flow, respectively.
This generator enables successive performance of the two functions corresponding to these two categories of applications. Switching from one to the other necessitates a modification of the tubing and of the hydraulic component.
Thus, this continuous flow generator is limited to distributing sterile liquid by a single type of action at one time, either dissection or lavage/rinsing.
Moreover, the jet is continuous and the generator was provided to feed only a single handpiece at a time.
Thus, it is necessary to change the mode of operation and the conduits each time a switch is made from pressure operation to flow operation, i.e., from the use of a dissection handpiece to a lavage/rinsing unit and vice versa.
The work is performed under aspiration of the operating liquid through the aspiration network, for example, that of the operating theater connected to the evacuation via a vacuum pump.
As the generator is a continuous source, the applications remain limited to those of a continuous jet with adjustable pressure or to diffusion by spraying for the purposes of lavage/rinsing or of irrigation.
Moreover, the advantages of pulsed jets which enable improvement of the precision of dissection work while reducing the pressure and the consumption of the liquid are known in surgery.
This work results from successive sets or trains of periodic pressurized liquid firing pulses, with the pause between the successive sets used for aspiration of the liquid fired and of the biological residues.
Although this pulsed operation enables improvement of the precision of the dissection, the depth of the incision is difficult to control, and efficacy is difficult to guarantee in shallow dissections. Moreover, the visibility of the operative field could be appreciably improved.